U.S. patent number 8,747,367 [Application Number 10/549,004] was granted by the patent office on 2014-06-10 for injection device.
This patent grant is currently assigned to Haselmeier GmbH. The grantee listed for this patent is Jochen Gabriel, Joachim Keitel. Invention is credited to Jochen Gabriel, Joachim Keitel.
United States Patent |
8,747,367 |
Keitel , et al. |
June 10, 2014 |
Injection device
Abstract
An injection apparatus has a barrel (50) that is adapted to
receive a container (108) with injection fluid (110). It further
comprises a piston rod (98), provided with a thread (100), for
expelling injection fluid (110) from such a container (108), which
piston rod (98) is guided relative to the barrel (50) in the axial
direction (112, 114). Additionally provided is a threaded part
(122) whose thread (120) is in engagement with the thread (100) of
the piston rod (98), which threaded part (122) is rotatable
relative to the piston rod (98) and relative to the barrel (50) in
order to set an injection dose, and, during an injection operation,
is prevented from rotating relative to the piston rod (98).
Inventors: |
Keitel; Joachim (Esslingen,
DE), Gabriel; Jochen (Stuttgart, DE) |
Applicant: |
Name |
City |
State |
Country |
Type |
Keitel; Joachim
Gabriel; Jochen |
Esslingen
Stuttgart |
N/A
N/A |
DE
DE |
|
|
Assignee: |
Haselmeier GmbH (St. Gallen,
CH)
|
Family
ID: |
34353566 |
Appl.
No.: |
10/549,004 |
Filed: |
July 28, 2004 |
PCT
Filed: |
July 28, 2004 |
PCT No.: |
PCT/EP2004/008422 |
371(c)(1),(2),(4) Date: |
September 14, 2005 |
PCT
Pub. No.: |
WO2005/046770 |
PCT
Pub. Date: |
May 26, 2005 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20060258988 A1 |
Nov 16, 2006 |
|
Foreign Application Priority Data
|
|
|
|
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Nov 3, 2003 [DE] |
|
|
203 17 377 U |
|
Current U.S.
Class: |
604/211 |
Current CPC
Class: |
A61M
5/31551 (20130101); A61M 5/31561 (20130101); A61M
5/31558 (20130101); A61M 2005/202 (20130101); A61M
5/31593 (20130101); A61M 5/31585 (20130101); A61M
2205/582 (20130101); A61M 2205/581 (20130101); A61M
5/20 (20130101); A61M 5/31563 (20130101) |
Current International
Class: |
A61M
5/00 (20060101) |
Field of
Search: |
;604/191,181,82,207-211,187 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2003-213971 |
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Oct 2003 |
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AU |
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41 12 259 |
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Oct 1992 |
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DE |
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694 20 297 |
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Sep 1994 |
|
DE |
|
699 00 026 |
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Aug 1999 |
|
DE |
|
100 47 637 |
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Apr 2002 |
|
DE |
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101 29 585 |
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Jan 2003 |
|
DE |
|
0 327 910 |
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Aug 1989 |
|
EP |
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0 897 728 |
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Feb 1999 |
|
EP |
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12 28 777 |
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Aug 2002 |
|
EP |
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1 656 170 |
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May 2006 |
|
EP |
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WO 99-38554 |
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Aug 1999 |
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WO |
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WO 00-41754 |
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Jul 2000 |
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WO |
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WO 01-95959 |
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Dec 2001 |
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WO |
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WO 03-011370 |
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Feb 2003 |
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WO |
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WO 03/011374 |
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Feb 2003 |
|
WO |
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WO 03-080160 |
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Oct 2003 |
|
WO |
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WO 03/086512 |
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Oct 2003 |
|
WO |
|
WO 2005-018721 |
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Mar 2005 |
|
WO |
|
Primary Examiner: Mehta; Bhisma
Assistant Examiner: Osinski; Bradley
Attorney, Agent or Firm: Oliver, Esq.; Milton Oliver
Intellectual Property LLC
Claims
The invention claimed is:
1. An injection apparatus comprising: a housing (50) configured to
receive a container (108) containing injection fluid (110); a
piston rod (98) having a longitudinal axis (112, 114) and being
provided with a thread (100), said piston rod (98) serving, in
operation, for expelling injection fluid (110) from such a
container (108), and being non-rotatably guided relative to the
housing (50) for movement in the direction of the longitudinal axis
(112, 114) thereof a threaded part (122) formed with a first thread
(120) which is in engagement with the thread (100) of the piston
rod (98), the position of the threaded part (122) relative to the
housing (50) being adjustable; a setting member (76) provided for
setting an injection dose by rotation of said setting member (76);
a coupling (84, 136) arranged between the setting member (76) and
the threaded part (122), said coupling (76) being closed during
setting of the injection dose and open during an injection process
so that the threaded part (122) is, for setting an injection dose,
rotatable relative to the piston rod (98) and relative to the
housing (50) and moves in the direction of the longitudinal axis
(112, 114) and relative to the piston rod (98) and relative to the
housing (50) during a dose-setting operation, and moves, during an
injection process, axially relative to the housing (50) in an
injection direction but is hindered against rotation relative to
the piston rod (98), the setting member (76) being so rotatable
arranged in the housing (50) that, for setting an injection dose, a
combined length of the housing (50) and the setting member (76) is
adjustable, from an initial combined length value, by a rotation of
said housing and said setting member with respect to each other,
said combined length being resettable, during an injection process,
to said initial combined length value by rotating said housing (50)
and said setting member (76) with respect to each other; a pushing
member (66) being provided, which is connected to the housing (50)
via a first drive connection (64, 70) and to the setting member
(76) via a second drive connection (86, 94), so that the pushing
member (66) moves relative to the housing in a predetermined
direction when the setting member (76) is moved, likewise in that
predetermined direction, by rotation relative to the housing (50)
and pushes said threaded member (122) and said piston rod (98) in
an injection direction during an injection process.
2. The injection apparatus according to claim 1, wherein the second
thread (86, 94) is implemented as a second drive connection for the
pushing member (66).
3. The injection apparatus according to claim 1, wherein the thread
pitches of the first, second, and third threads are dimensioned
such that, during the setting operation, a rotation of the setting
member (76) has substantially no influence on the location of the
piston rod (98) relative to the housing (50).
4. The injection apparatus according to claim 1, further comprising
a torsional spring (148), which is arranged in such a way that
energy is stored in it when a dose is set, and energy is released
from it during an injection operation.
5. The injection apparatus according to claim 4, wherein the
torsional spring (148) is arranged between the setting member (76)
and the pushing member (66), a relative rotation between those
parts modifying the torque generated by the torsional spring
(148).
6. The injection apparatus according to claim 5, wherein the
torsional spring (148) is joined nonrotatably but axially
displaceably to the pushing member (66).
7. The injection apparatus according to claim 1, wherein a detent
connection (64, 131) is provided between the housing (50) and a
part (122) connectable via a controllable coupling (84, 136) to the
setting member (76).
8. The injection apparatus according to claim 7, wherein there is
provided, in the housing (50), a spline set (64) that coacts with a
detent member (131) that is axially displaceable relative to the
barrel housing (50), in order to produce rotational detent
positions that are independent of the relative axial locations of
the detent member (131) and housing (50).
9. The injection apparatus according to claim 8, wherein the detent
connection (64, 131) is implemented in such a way that, by means of
a first predetermined minimum torque, it is adjustable in a
rotation direction that increases the injection dose, and by means
of a second predetermined minimum torque, it is adjustable in a
rotation direction that decreases the injection dose.
10. The injection apparatus according to claim 7, wherein the
detent connection (64, 131) is implemented in such a way that, by
means of a first predetermined minimum torque, it is adjustable in
a rotation direction that increases the injection dose, and, by
means of a second predetermined minimum torque, it is adjustable in
a rotation direction that decreases the injection dose.
11. The injection apparatus according to claim 10, wherein the
first and the second predetermined minimum torques are of
substantially equal magnitude.
12. The injection apparatus according to claim 1, wherein a
follower (128) is provided, coupled to said setting member (76) in
such a way that a dose-setting rotation of the setting member (76)
is transmitted to the follower, but a rotation of the setting
member occurring during an injection is not transmitted to the
follower (128).
13. The injection apparatus according to claim 12, wherein said
threaded part (122) is connected to said follower (128) in such a
way that a rotation of the follower (128) is transmitted to the
threaded part (122), but an axial displacement of the follower
(128), relative to the housing (50), is not transmitted to the
threaded part.
14. The injection apparatus according to claim 12, wherein the
pushing member (66) is provided on its patient-proximal side with a
contact member (69) which is configured for contact against a
patient-remote side (125) of the threaded part (122) in order,
during an injection, to displace the piston rod (98) via the
threaded part (122) in a patient-proximal direction, and to expel
injection fluid (110) from the container (108).
15. The injection apparatus according to claim 1, wherein said
first drive connection is configured as a second thread (86, 94),
and said second drive connection is configured as an axial guide
(64, 70).
16. The injection apparatus according to claim 15, further
comprising a third threaded connection (62, 74), arranged between
said housing (50) and said setting member (76), serving for length
adjustment purposes.
17. The injection apparatus according to claim 16, wherein portions
of the setting member (76) that are located adjacent the third
thread (62, 74) are provided with scale values (78) for displaying
the injection dose that is set.
18. The injection apparatus according to claim 17, wherein the
housing (50) is provided with a window (52) for displaying at least
one of the scale values (78).
19. The injection apparatus according to claim 16, wherein the
second thread (86, 94) and the third thread (62, 74) have identical
thread directions.
20. The injection apparatus according to claim 19, wherein the
thread pitch of the third thread (62, 74) is greater in absolute
value than the thread pitch of the second thread (86, 94).
21. The injection apparatus according to claim 19, wherein the
thread direction of the first thread (100, 120) corresponds to that
of the third thread (62, 74).
22. The injection apparatus according to claim 21, wherein the
thread pitch of the first thread (100, 120) is smaller in absolute
value than the thread pitch of the third thread (62, 74).
23. The injection apparatus according to claim 22, wherein said
coupling (84, 136), is controllable between an open state and a
closed state and, in said closed state, enables transfer of torque
from the setting member (76) to the follower (128).
24. The injection apparatus according to claim 23, wherein the
controllable coupling (84, 136) is so configured that it transfers
the rotational motion of the setting member (76) to the follower
(128) during the setting of an injection dose.
25. The injection apparatus according to claim 23, wherein the
controllable coupling (84, 136) is so configured that it does not
transfer a rotational motion of the setting member to the follower
(128) during an injection.
26. The injection apparatus according to claim 23, wherein the
controllable coupling (84, 136) is controllable by the injection
operation in such a way that, after completion of an injection,
said coupling returns to a closed state, and remains closed during
dose-setting, so that a dose-setting rotation of the setting member
(76) is transferred to the threaded part (122) by the controllable
coupling (84, 136).
27. The injection apparatus according to claim 23, wherein the
controllable coupling (84, 136) is implemented so that it opens
during a component movement occurring at the beginning of an
injection.
28. The injection apparatus according to claim 16, wherein the
respective thread pitches or steepnesses of said first, second and
third threaded connections are selected such that, during setting
of an injection dose, the displacement of the pushing member (66)
in a predetermined direction is at least as large as the
displacement of said threaded part (122) in said predetermined
direction.
Description
CROSS-REFERENCE
This application is a section 371 of PCT/EP2004/008422, filed Jul.
28, 2004, claiming priority from German application DE 203 17
377.5, filed Nov. 3, 2003, the entire content of which is hereby
incorporated by reference.
FIELD OF THE INVENTION
The invention concerns an injection apparatus in which a piston rod
is guided in the axial direction.
BACKGROUND
With injection apparatuses, it is desirable for their operation to
be easily understandable, i.e. intuitive, and for the patient to
have good control over the injection operation, i.e. to be able to
understand what is happening.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to make a new injection
apparatus available.
According to the invention, this object is achieved by an injection
apparatus in which a barrel holds a container of injectable fluid,
and a threaded part is in engagement with a thread on a piston rod,
the threaded part being rotatable during a dose-setting operation
but not during an injection operation driven by the piston rod.
Before an injection, the patient sets a desired injection dose by
rotating the threaded part relative to the piston rod and relative
to the barrel, the threaded part being displaced axially relative
to the piston rod and relative to the barrel.
After insertion of the needle, the patient then performs the
injection, the threaded part being displaced axially in the
injection direction relative to the barrel and moving together with
the piston rod, i.e. not performing a relative motion relative to
the latter, since it is prevented from rotating relative to it.
A sophisticated interplay of rotary motions and axial motions is
thus used on the one hand to set the dose, and on the other hand to
inject the previously set dose after the setting operation.
Operation in this manner is intuitively easy to understand.
If the patient has inadvertently set the dose too high, he can
reduce it again. With an apparatus according to the invention, this
"dose correction" is just as simple as setting the dose itself, and
is easy to understand.
Further details and advantageous refinements of the invention are
evident from the exemplary embodiments, in no way to be understood
as a limitation of the invention, that are described below and
depicted in the drawings.
BRIEF FIGURE DESCRIPTION
FIG. 1 is a side view of the barrel of an injection apparatus
according to a preferred embodiment of the invention;
FIG. 2 is an axial section through the barrel of FIG. 1, viewed
along line II-II of FIG. 3;
FIG. 3 is a view in the direction of arrow III of FIG. 2;
FIG. 4 is a side view of a setting member serving for dose setting,
which is also referred to as a "scale tube";
FIG. 5 is a longitudinal section through the setting member of FIG.
4;
FIG. 6 is a plan view of a pushing member that, in this embodiment,
is provided with an external thread;
FIG. 7 is a longitudinal section through the pushing member of FIG.
6, viewed along line VII-VII of FIG. 8;
FIG. 8 is a view in the direction of arrow VIII of FIG. 6;
FIG. 9 is a longitudinal section through a partially assembled
injection apparatus according to the invention, in its state after
an injection and before an injection dose is set;
FIG. 10 is a longitudinal section through an arrangement according
to FIG. 9, but after an injection dose is set;
FIG. 11 is a side view in the direction of arrow XI of FIG. 9, the
injection apparatus being in the position for the zero dose;
FIG. 12 is a side view analogous to FIG. 11, the injection
apparatus being, however, in a position for the 40-unit dose;
FIG. 13 is a plan view of a piston rod, provided with an external
thread (left-hand thread), that serves to expel injection fluid
from a container (cartridge), viewed in the direction of arrow XIII
of FIG. 14;
FIG. 14 is a section through the piston rod, viewed along line
XIV-XIV of FIG. 13;
FIG. 15 is a plan view of a threaded part that is also referred to
as an "advancing part";
FIG. 16 is a longitudinal section through the threaded part of FIG.
15, viewed along line XVI-XVI of FIG. 17;
FIG. 17 is a section viewed along line XVII-XVII of FIG. 15;
FIG. 18 is a plan view of a follower that serves, in certain
operating states, to couple the threaded part (FIGS. 5 through 17)
to the setting member (FIGS. 4 and 5) in such a way that said part
rotates along with said member, but is freely displaceable axially
relative to the setting member;
FIG. 19 is a longitudinal section through the follower of FIG. 18,
viewed along line XIX-XIX of FIG. 20;
FIG. 20 is a section viewed along line XX-XX of FIG. 18;
FIG. 21 is a section through a guidance member that serves for
axial guidance of the piston rod in the barrel, viewed along line
XXI-XXI of FIG. 22;
FIG. 22 is a view of the guidance member of FIG. 21 in the
direction of arrow XXII of FIG. 21;
FIG. 23 is a schematic longitudinal section through an injection
apparatus in the assembled state and before an injection dose is
set;
FIG. 24 is a section viewed along line XXIV-XXIV of FIG. 23;
FIG. 25 is a section viewed along line XXV-XXV of FIG. 23;
FIG. 26 is a section viewed along line XXVI-XXVI of FIG. 23;
FIG. 27 is a longitudinal section analogous to FIG. 23, but after
the setting of an injection dose;
FIG. 28 is a longitudinal section analogous to FIGS. 23 and 27, but
during an injection;
FIG. 29 shows a variant of the injection apparatus according to
FIGS. 1 through 28, the injection operation being assisted by an
energy that is stored in the apparatus by the user while setting
the dose;
FIG. 30 shows a second variant that likewise uses the servo
assistance of FIG. 29, but in which measures are taken so that the
length of torsional spring 148 that is used does not change during
operation;
FIG. 31 is a section viewed along line XXXI-XXXI of FIG. 30;
and
FIG. 32 is an overall depiction of the injection apparatus.
DETAILED DESCRIPTION
The description below first explains the general construction and
mode of operation of the invention with reference to greatly
enlarged and schematized depictions. That is followed by a specific
exemplary embodiment in the form of a so-called "pen injector." In
the description, the same reference characters are used in each
case for identical or identically functioning parts, and those
parts are usually described only once.
Directions of motion are indicated in the manner usual in medicine,
i.e.
proximal=toward the patient, i.e. in the direction toward the
injection needle;
distal=away from the patient, i.e. in the direction away from the
injection needle.
FIG. 1 is a side view of a barrel 50 that has a cylindrical outer
side comprising a window 52 that serves for (mechanical) display of
the injection dose (see FIG. 12, where a display of 40 units is
depicted as an example).
Barrel 50, made of a suitable plastic, has an external tube 54 and
an internal tube 56 concentric therewith, which are joined to one
another by a bridge part 58 (FIGS. 2 and 3) in such a way that an
annular space 60 is formed between them. Internal tube 56 has a
length that, in the exemplary embodiment, is equal to approximately
four-tenths of the length of external tube 54. Its distal end is
labeled 61.
Implemented in external tube 54 is an internal thread 62 that, in
the exemplary embodiment, is implemented as a coarse thread having
an approximately rectangular cross section of the threads, in this
case (as an example) as a left-hand thread having a pitch of 10 mm
per revolution (the depictions are enlarged for illustrative
purposes).
Provided in this embodiment in internal tube 56 is a spline set 64
whose shape is evident from FIGS. 2 and 3. It has, in this case,
twenty longitudinal grooves 65, between which are elevations 67.
FIGS. 24 and 25 show spline set 64 at a greatly enlarged scale. It
serves for axial guidance of a pushing member 66 that is depicted
in FIGS. 6 through 8. The latter has at its proximal end a head
portion 68 with an enlarged diameter, and provided on that portion
is a spline set 70 that is complementary to spline set 64 and is
guided therein (see, for example, FIGS. 9 and 10). The proximal end
of head portion 68 is labeled 69.
External thread 74 of a setting member 76 (FIGS. 4 and 5) is guided
in internal thread 62 (FIG. 2). That member has, between its
threads, surfaces on which is applied a dose scale 78 ranging, for
example, from "0" to "60," so that setting member 76 can also be
called a "scale tube."
FIG. 4 shows some of the scale numbers by way of example. Member 76
has at its distal end a setting knob 80 which serves for setting
the injection dose and with which the patient injects, by axial
pressure, the dose that was set (see FIG. 28 below). Provided in
knob 80 is a central opening 82 at whose rim a tooth set 84 is
implemented on the proximal side.
Implemented in the interior of setting member 76, on a thread
carrier 90 projecting radially inward, is an internal thread 86
that is implemented here as a left-hand coarse thread having a
pitch of, for example, 7 mm per revolution. Its threads preferably
also have a rectangular cross section.
As is apparent from FIG. 9, thread carrier 90 is provided at a
distance from proximal end 88 of setting member 76 such that the
latter can be screwed completely into annular space 60 (FIG. 2),
thread carrier 90 coming to a stop with its proximal side 92
against distal end 61 of internal tube 56. The distal side of
thread carrier 90 is labeled 93.
FIGS. 6 through 8 show pushing member 66. This has an outer thread
(left-hand thread) 94 that, in the assembled state (FIGS. 9 and
10), engages into internal thread 86 of setting member 76, so that
a rotation of setting member 76 in which it is rotated in the
direction of an arrow 96 (FIG. 4) moves setting member 76 in the
distal direction, while the same rotation moves pushing member 66
in the proximal direction relative to setting member 76. Pushing
member 66 has a cylindrical internal opening 67 that transitions,
at the left in FIG. 7, into shoulder 69 extending radially
outward.
FIG. 9 shows the above-described parts prior to setting of an
injection dose, the "0" dose being displayed in window 52 as shown
in FIG. 11. Proximal end 69 of pushing member 66 is here at a
distance L1 from the proximal end of bridge part 58.
FIG. 10 shows the parts after setting of a large injection dose,
namely after three complete revolutions of setting member 76. The
latter has thereby been displaced, for example, 30 mm in the distal
direction. At the same time, pushing member 66 has been displaced a
distance L3, for example 21 mm, in the proximal direction relative
to thread carrier 90. The effect is that proximal end 69 of pushing
member 66 has been displaced, as compared with FIG. 9, a distance
L4=L2-L3 (1) in the distal direction, i.e. in this case 30-21=9 mm
(2). Those 9 mm are the distance that then determines the injection
dose that is injected. This is the result of the fact that pushing
member 66, via its spline set 70 (FIGS. 6 and 8), is guided axially
in spline set 64 of barrel 50.
With regard to pushing member 66, the same effect would result if
the latter were axially guided in part 90 and were driven by an
internal thread in internal tube 56. This is referred to as
"kinematic reversal," i.e. the two drive connections for pushing
member 66 are interchangeable. With the latter variant, the thread
would need to be arranged between the outer side of part 68 and the
inner side of internal tube 56, i.e. in place of axial guidance
system 64, 76. The version depicted is preferred, however, because
spline set 64 in the context of the present invention also has the
function of a ratchet that becomes effective during dose
setting.
Dose setting thus produces oppositely directed motions, i.e.
setting member 76 moves rapidly in the distal direction, and
pushing member 66 simultaneously moves, somewhat more slowly,
relative to setting member 76 in the proximal direction; as-the
final result, proximal end 69 of pushing member 66 is displaced a
relatively short distance L4 in the distal direction. The
arrangement according to FIGS. 9 and 10 thus acts as a linear gear
linkage, and the large motion of setting member 76 has the
advantage that a dose can be displayed (in window 52) with large,
easily readable digits 78 (see FIGS. 11 and 12). A dose that was
inadvertently set too high can also be corrected manually by
turning the setting knob 80, distance L4 then becoming smaller
again. In addition, the patient can accurately observe in window
52, during injection, how much he has already injected. Many
patients want to have this information.
FIGS. 13 and 14 show a threaded rod 98 that is provided with a
rectangular coarse thread 100 that, as depicted, is a left-hand
thread and has a thread pitch equal, in this example, to 3 mm per
revolution. Piston rod 98 has at its distal end a stop 102 that
prevents it from being screwed all the way out; and at its proximal
end, i.e. at the bottom in FIGS. 13 and 14, it has a pusher plate
104 with which, in the assembled state as shown in FIG. 23, it
rests against rubber piston 106 of a cartridge 108 that is filled
with injection fluid 110. It additionally has a longitudinal groove
112 with which it is axially guided in a part 116 that is depicted
in FIGS. 21 and 22 and that engages with a protrusion 114 into
longitudinal groove 112. Part 116 has on its outer side a portion
comprising a spline set 117 with which, in the assembled state, it
is guided in spline set 64 of barrel 50. The result is to create an
axial guidance system 112, 114 of piston rod 98 relative to barrel
50.
Part 116 as shown in FIGS. 21 and 22 fits with its external tooth
set 117 into spline set 64 of barrel 50, and in the assembled state
is retained in that position because, according to FIG. 23, it
rests with its proximal end against the distal end of cartridge
108.
When the apparatus is opened by removing a proximal barrel part 107
from barrel part 50 (FIG. 23), part 116 is then no longer braced by
cartridge 108 and can be pulled out of spline set 64 as far as a
stop. It thereby becomes freely rotatable and allows piston rod 98
to be screwed in the distal direction back into its initial
position, by rotation relative to thread 98. This allows a fresh,
full cartridge 108 to be loaded.
During an injection, piston rod 98 displaces piston 106 in the
proximal direction, i.e. downward (FIG. 23), and thereby expels
injection fluid 110 from container 108. The latter can be replaced
when fluid 110 is consumed. The apparatus is usually delivered
empty, i.e. without a container (cartridge) 108. Piston rod 98 does
not perform any rotary motion during the injection, but instead
moves linearly in the proximal direction.
External thread 100 of piston rod 98 is guided in an internal
thread 120 of a threaded part 122 (FIGS. 15 through 17) that
hereinafter is also referred to as the "advancing part." When
threaded part 122 is rotated, it causes an axial displacement of
piston rod 98 relative to this part 122. This operation is referred
to as the advancing (setting) of the piston rod (98), hence the
name "advancing part."
Part 122 has on its cylindrically configured outer side 123 a
longitudinal groove 124. Into this engages a radially inwardly
projecting protrusion 126 (FIG. 20) of a follower 128 (FIGS. 18
through 20). The latter has a cylindrical internal opening 130 that
is slidingly displaceable on cylindrical outer side 123 of threaded
part 122, protrusion 126 sliding in longitudinal groove 124 and
connecting parts 122, 128 nonrotatably to one another (see FIGS. 23
and 26). Cylindrical outer side 123 transitions at the left into a
radially outwardly extending shoulder 125 (see FIGS. 15 through
17).
Advance member 122 has on its proximal side a head part 127 made of
an elastic plastic. Head part 127 is integral with a radially
resilient detent tongue 129 at whose free end is located a detent
member 131 that, as shown in FIG. 25, rests with preload against
axial internal spline set 64 of barrel 50 and can latch into the
longitudinal grooves 65 of that spline set 64.
During an injection, head 127 along with its detent member 131 is
displaced axially in spline set 64.
The coaction of detent member 131 and spline set 64 causes the
patient to hear and feel twenty clicks for each revolution of
setting member 76 (FIGS. 4 and 5), so that he/she can also set the
dose by ear or by feel, since an audible and perceptible signal is
generated for each unit. This is important because many diabetics
have poor eyesight.
In addition, a dose cannot unintentionally be shifted once it has
been set, since a predetermined minimum torque is necessary for any
adjustment in either rotation direction.
Lastly, the coaction between detent member 131 and detent spline
set 64 also means that a torsional spring 148 as shown in FIGS. 29
through 31 can become effective only when the patient presses
(according to FIG. 28) on follower 128 and thereby opens coupling
84, 136, since the connection of detent member 131 to setting
member 76 is then interrupted, and torsional spring 148 can
consequently rotate setting member 76 or at least can assist the
rotation of setting member 76.
Spline set 64 thus has several functions in the context of the
exemplary embodiment, since it serves for nonrotatable connection
between barrel 50 and parts that must be nonrotatably connected to
it, and it also serves to create a detent connection whose function
is independent of the axial position of head part 127.
Follower 128 (FIGS. 18 through 20) has at its distal end an
actuation plate 132 onto which the patient presses in the proximal
direction when injecting (see FIG. 28). Arranged at a distance from
plate 132 is a coupling flange 134, which is equipped on its distal
side, i.e. on the right in FIGS. 18 and 19, with a tooth set 136
that serves for engagement with tooth set 84 depicted in FIG. 5
and, when engaged, couples parts 76 and 128 non-rotatably to one
another.
According to FIG. 23, coupling flange 134 is impinged upon in the
distal direction by a compression spring 138. Spring 138 is
arranged between coupling flange 134 and a support flange 140 of
setting member 76, so that tooth sets 84, 136 are in engagement
with one another as long as the patient does not press on actuation
plate 132. When he does so, spring 138 is then compressed and tooth
sets 84, 136 are brought out of engagement.
When setting an injection dose, the patient rotates setting member
76 relative to barrel 50, and in the course of that rotation
follower 128 is also rotated, by way of the (closed) coupling 84,
136, through the same rotation angle relative to barrel 50. Because
follower 128 is rotating, threaded part 122 also rotates (by way of
guidance system 124, 128) relative to barrel 50, the previously
described detent connection 64, 131 being actuated in that
context.
Because, on the one hand, threaded part 122 is rotating relative to
barrel 50 but, on the other hand, piston rod 98 cannot rotate
relative to barrel 50 because (as shown in FIG. 24) it is axially
guided by protrusion 114, piston rod 98 moves in the proximal
direction relative to threaded part 122, but for the reasons
described below, its position relative to barrel 50 does not change
in that context.
Because setting member 76 is rotating relative to barrel 50, but
pushing member 66 is not rotatable relative to barrel 50 as a
result of guidance system 64, 70 (FIG. 9), pushing member 66 is
displaced relative to barrel 50 in the distal direction by threads
86, 94. The distal motion of pushing member 66 relative to barrel
50 is preferably of the same magnitude as the proximal motion of
piston rod 98 relative to threaded part 122.
One consequence of the proximal motion of piston rod 98 relative to
threaded part 122 is that threaded part 122 is displaced distally
relative to barrel 50, while piston rod 98 does not move relative
to barrel 50.
(Alternatively, it would theoretically also be possible for piston
rod 98 to be displaced relative to barrel 50 in the proximal
direction, while threaded part 122 does not move in the axial
direction, i.e. remains stationary. This is prevented, however, by
the fact that threaded part 122 can easily execute a motion in the
distal direction relative to barrel 50, whereas conversely a motion
of piston rod 98 in the proximal direction is greatly impeded by
the friction of piston 106 (FIG. 23) in container 108, so that this
piston 106 acts as an abutment that prevents a motion of piston rod
98 relative to barrel 50 during the setting operation.)
The conditions occurring in the exemplary embodiment as setting
member 76 was rotated through three revolutions were explained in
FIG. 10. That member was, as a result, displaced upward a distance
L2 =30 mm. At the same time, pushing member 66 was displaced
downward a distance L3=21 mm relative to setting member 66, so that
in accordance with equations (1) and (2), pushing member 66 moved a
distance L4=L2-L3=30-21=9 mm upward.
With three complete revolutions of part 76, threaded part 122
(FIGS. 15 through 17) also executes three complete revolutions,
thereby causing piston rod 98 in FIG. 23 to be displaced downward 9
mm, i.e. exactly the distance L4.
This means in practical terms that in FIG. 23, during a setting
motion of setting member 76 (for dose-setting purposes) the
location of pusher plate 104 of piston rod 98 relative to rubber
piston 106 remains unchanged, i.e. piston rod 98 maintains its
location relative to barrel 50 during the setting operation. A
change in that location occurs only upon injection. This is a
consequence of the fact that the directions and pitches of the
three threads described above have a predetermined relationship to
one another, and that relationship can be selected in accordance
with requirements.
FIG. 27 is an expanded depiction analogous to FIG. 10, and it is
evident from it that the location of piston rod 98 has remained
unchanged as compared with FIG. 23 despite the setting
operation.
FIG. 28 shows an intermediate state in the course of an injection.
That injection is initiated by the fact that the patient presses on
plate 132 with a force P in the proximal direction. Spring 138 is
thereby compressed, and coupling 84, 136 is opened.
By means of force P, optionally amplified by the torque of a
torsional spring 148 described below, setting member 76 is screwed
back into the position according to FIG. 9 and FIG. 23, since it
has a coarse thread that automatically executes a screwing motion
under axial pressure. Setting member 76 also causes pushing member
66 to be screwed back into the position shown in FIG. 9 and FIG.
23.
The location of piston rod 98 relative to threaded part 122 remains
unchanged during the injection operation, and because pushing
member 66 moves downward a distance L4 (FIG. 10) during that
operation, threaded part 122 is displaced by pushing member 66 a
distance L4 downward, i.e. in the proximal direction, since
shoulder 69 of pushing member 66 pushes in the proximal direction
against shoulder 125 of threaded part 122.
Piston rod 98 is thus also displaced downward a distance L4 by
threaded part 122, pushing rubber piston 106 (FIG. 23) a distance
L4 downward in order to expel a corresponding quantity of injection
fluid 110 from cartridge 108. The result is therefore that a
quantity of injection fluid corresponding to the previously set
distance L4 is injected.
Because setting member 76 rotates during the injection operation,
the patient can follow the sequence of the injection in window 52
as if in a movie, i.e. he knows at every moment how much he has
already injected. When the number "0" appears in scale window 52,
the patient knows that he has injected his entire dose.
A "0" is therefore automatically displayed in window 52 at the end
of an injection (see FIG. 11) and a new setting operation can
begin, so that no calculations, resetting operations, or the like
are required of the patient.
FIG. 29 shows a variant in which a torsional spring 148 is arranged
between setting member 76 and pushing member 66. Distal end 150 of
spring 148 is nonrotatably connected to setting member 76, and
proximal end 152 is nonrotatably connected to the distal end of
pushing member 66.
Before an injection, the patient rotates setting member 76 and as a
result screws it out of barrel 50, as described with reference to
FIGS. 9 and 10. In that context, setting member 76 and pushing
member 66 rotate relative to one another as described with
reference to FIGS. 9 and 10. This rotation loads spring 148
torsionally; this can be reinforced by installing spring 148 with a
predetermined preload.
The relative rotation between setting member 76 and pushing member
66 is reversed during an injection, and the injection apparatus
returns, for example, from the position shown in FIG. 10 to the
position shown in FIG. 9 as the dose that was set is injected.
The friction of piston 106 (FIG. 23) in container 108 must be
overcome in this context, and this is facilitated by the energy
that was stored in torsional spring 148 when setting the dose, thus
making the injection easier for the patient.
As a comparison of FIGS. 9 and 10 shows, in FIG. 29 spring 148
would not only be loaded in tension but also pulled lengthwise when
an injection dose is set; conversely, it would be greatly
compressed during an injection, which might cause space
problems.
These space problems are avoided in the version according to FIG.
30, in which a displacement member 154 is provided that slides on
the cylindrical outer surface of pushing member 66. Displacement
member 154 has a protrusion 156 (FIG. 31) that projects radially
inward, and pushing member 66 is provided with a longitudinal
groove 158 into which that protrusion 156 engages. Proximal end 158
of spring 148 engages, as depicted, into an opening 160 of
displacement member 154.
By means of the force of spring 148, displacement member 154 is
always held in contact against distal side 93 of thread carrier 90,
so that in the variant according to FIGS. 30 and 31, the length of
spring 158 does not change during dose setting and injection. As
pushing member 66 is rotated, displacement member 154 also executes
a corresponding rotation relative to thread carrier 90; for that
reason, these parts should be manufactured from a plastic having a
low coefficient of friction, or a washer made of PTFE or the like
can be provided between these parts.
As already described, the energy stored in spring 148 is not
released until coupling 84, 136 is opened by a pressure on plate
132 (see FIG. 28), since this interrupts the connection to detent
member 131 depicted in FIG. 25; before an injection, that member
retains spring 148 immovably in its tensioned position provided the
detent force is sufficient therefor.
FIG. 32 is an overall depiction of the injection apparatus. The
upper, distal part corresponds to the depiction in FIG. 23, to
which the reader may therefore be referred. Cartridge 108 is guided
in proximal barrel part 107. The latter has at the bottom a thread
168 for screwing on threaded part 170 of a needle 172 whose distal
part, in known fashion, pierces a rubber membrane (not depicted) of
cartridge 108 and thereby creates a connection between needle 172
and injection fluid 110 in cartridge 108, as is known to one
skilled in the art. Needle 172 is usually replaced before each
injection.
Many variants and modifications are, of course, possible in the
context of the present invention.
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